Heavy snow brought travel delays in the mountains, with nearly 4 feet of snow at and above pass levels. Heavy rain brought ash flows and debris flows over some recently burned areas.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS STO wrote it up.
Heavy snow brought travel delays in the mountains, with nearly 4 feet of snow at and above pass levels. Heavy rain brought ash flows and debris flows over some recently burned areas.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Sacramento, CA wrote its last area forecast discussion before the first event at Nov 27, 3:32 PM PST, 8 hours 28 minutes earlier.
Area Forecast Discussion National Weather Service Sacramento CA 332 PM PST Tue Nov 27 2018 .SYNOPSIS... An unsettled weather week will keep rain and wind in the valleys and snow in the mountains. Snow will remain along the highest peeks tonight through Wednesday, with scattered rain showers in the valley. A stronger/colder weather system will move in Wednesday night through early Friday, bringing some of the lowest snow levels thus far this season. A brief break Friday before yet another system moves in Saturday. Keep those umbrellas handy and snow supplies in your car if heading in the mountains the next 5 days. && .DISCUSSION... The first in a series of weather systems is moving through NorCal today. A band of rain and high elevation snow has been slowly moving through NorCal all day, and is currently pushing through the Sacramento valley this afternoon. Scattered valley rain showers will linger in the valley through this evening and overnight hours with snow continuing to impact passes above 6000 feet. Therefore, the winter weather advisory will remain in affect through Wednesday. A second, more impactful system, is on the heels of this first system later Wednesday night and Thursday. This next system will have heavier precipitation, possible thunderstorms, gusty winds and heavy snow over the mountains with lowering snow levels. Due to the potential for thunderstorms, have issued a flash flood/debris flow watch for the Camp, Mendocino Complex and Carr, Hirz-Delta fires for late Wednesday night through Thursday morning. The winter storm watch has been upgraded to a warning for the Sierra Nevada mountains and extreme southern Cascade Range. Somewhat drier and more settled weather returns Friday, but shower chances linger over the mountains. MEAD && .EXTENDED DISCUSSION (Saturday THROUGH Tuesday) The third and final disturbance within the trio of Pacific systems will take aim at the Northern California coast on Saturday morning. While well advertised by the latest model guidance, uncertainty still looms with expected impacts over the region. The GFS and European solutions offer different perspectives of this system with the former continuing to favor heavier precipitation. Given this feature currently resides near the Aleutians across far southwestern Alaska, much will likely change in the upcoming days. At this point, expect additional rainfall to the region with further snow accumulations over the mountains. Snow levels could drop to as low as 4,000 feet given the cold air accompanying this third system. One to two additional feet of snow is possible which would be on top of what falls the next few days. Ultimately this may lead to challenging mountain travel on Saturday. In the wake of this system, some lingering showers may be possible over the mountains on Sunday as a weakening upper trough sits overhead. Residual cloud cover should encourage slightly below normal daytime temperatures to conclude the weekend. Looking into next week, a lull in the pattern is anticipated as the next weather maker sits well offshore. Light northerly flow is expected at the surface with wind fields calming overnight supporting chilly overnights. On Monday and Tuesday mornings, Valley lows are forecast to be in the low to mid 30s with teens prevailing over mountain locales. Abundant sunshine during the daytime should bring numbers a bit closer to climatology. The next rainfall chances should hold off until the middle of next week, but a great deal of uncertainty exists. BRO && .AVIATION... Low visibility/ceilings continue at all sites due to rain or lingering valley fog. Periods of rain will continue overnight along with IFR/MVFR ceilings/visbys. Another round of precipitation enters the southern Sacramento valley near 10Z tomorrow. Timing of this next precipitation may still need to be adjusted in later forecasts. && .STO WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 10 PM PST Wednesday for West Slope Northern Sierra Nevada-Western Plumas County/Lassen Park. Flash Flood Watch from Wednesday evening through Thursday morning for the Mendocino Complex, the Carr, Delta-Hirz and Camp burn areas. Winter Storm Warning from 10 PM Wednesday to 4 AM PST Friday above 4000 feet for West Slope Northern Sierra Nevada-Western Plumas County/Lassen Park. &&
The Beale AFB radar (KBBX), 24 km away, was scanning. The volume nearest the first event began at 08:01 UTC.
4 flood, 2 debris flow, 2 heavy snow, 1 flash flood. Local standard time, as filed.
Flooding caused traffic delays and one hour of road closures on northbound and southbound Highway 99 from Neal Road to Estates Drive in Chico. Sheetflow was reported from heavy rain off of recently burned areas from the Camp Fire.
There were 10 slides into drainage systems along SR70, withing the Camp Fire burned area. The Concow/Pulga area was still under a mandatory evacuation order due to the Camp Fire. An automated gage at Durham reported very heavy rain from 1-2 pm of 1.64 and a second hour between 2-3 pm of 1.80.
Storms with heavy rain caused mudslides and debris flows on Highway 70 in the Pulga area. Debris flows clogged drains along the roadway. Trees along on roadway had to be removed. Highway 70 east of the West Branch of the Feather River was closed.
Heavy snow impacted mountain travel over Sierra passes, with snow totals of nearly 4 feet. Caltrans reported a storm total of 46 of snow measured by Castle Peak along I-80. Kirkwood Ski Resort reported 46, Squaw Alpine 45, Bear Valley 25, Kyburz had 10, with 1 down to Camino, elevation 3100'.
Heavy snow impacted mountain travel with delays and chain controls. There was 32 of snow reported at Lower Lassen Peak.
Heavy rain caused sheet flow from the Camp Fire burn scar, which flooded Highway 99 near Neal Road.
Flooding was reported at Honey Run Road and Horse Run Lane in Chico, due to local ponding of water and runoff from the Camp Fire burn scar.
A vehicle was reported stuck in flood waters up to mirrors in about 3.5 feet of water.
The Butte County Sheriff's Office issued an evacuation order for Honey Run Road due to flooding, from the 200 block to Skyway including Horse Run Lane. Nearly 100 cars were trapped for at least an hour on Honey Run Road, as two separate debris flows and flooding blocked cars from evacuating safely. Officials from the Butte County Sheriff’s Office confirmed the backup was up to two miles long. An automated gage at Durham reported very heavy rain from 1-2 pm of 1.64 and a second hour between 2-3 pm of 1.80.
Water rescuers were later called out to Honey Run Road in the lower area of Butte Creek Canyon after a white Jeep Cherokee was reported floating down Butte Creek. |The U.S. Army mobilized 19 high water vehicles to rescue the people who were trapped. Evacuation warnings were in place for the Hamlin Canyon and Lower Neal zones, and on the west side of the county at Hegan Lane south to Highway 162 to the Sacramento River.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2018Every state in 2018This day in weather historyWarnings in California, November 2018
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 789601, 789598, 794023, 789562, 789572, 794025, 794026, 794027, 789599.